This paper studies the deformation and failure of a controlling holding-plate rock stratum when large area is extracted continuously, from the view point of 3-D space, it also studies the essential relationship between surface subsidence and fracture and instability holding-plate as well as relevant features.
本文从三维空间角度来研究地下连续大面积开采时托板控制岩层的变形破坏规律，研究地表沉陷与托板破断失稳的本质联系和相关特征。
It's orientated by outer circle of workpiece itself and grinded by support of a supporting plate.
外圆无心磨削是不定心的磨削 ,由托板支承靠工件自身外圆定位进行磨削。
